Flasher



May 5', 1931.

G. Ii. BOSSARD- 1,803,590

FLASHER Original Filed Nov. 2, 1928 3 Sheets-Sheet l \QNVENTOR inflame/WC BY A TTORNEYJ 15, .1931. G. L. BOSSARD ,5

FLASHER Original Filed Nov. 2. 1928 3 Sheets-Sheet 2 INVEEVTOR BY MM 7 A TTORNE Y 3 Sheets-Sheet 3 IN VE N TOR A TTORNE Y FLASHER ca. L, BossARD Original Filed Nov.

May 5, 1931,

Patented May 5, 1931 GISBERT L. BOSSAR-D, OF DAYTON, OHIO, ASS

G-NOR TO GENERAL KONTROLAR COIVIPANY,

ING, OF DAYTON, (EH15), A. CORPORATION OF OHIO FLASHER Application filed November 2, 1928, Serial This invention relates to circuit controllers of the type employed for the intermittent energization or lighting of electric lights or other electrical loads.

,5 C'ne object of the invention is the provision of an automatic circuit controller embodying a driving element and an operated member to which the driving clement imparts a snap motion as the driving element is electrically operated the various parts of the circuit controller being separately attached to an integral supporting member, and the parts being of simple construction wvith a minimum number of articulated connections.

Another object of the invention is the provision of a circuit controller having field'magnet rigidly attached to a supporting member on which the armature of the magnet is rotatably mounted, the magnet poles being so attached to the supporting member as to permit ready removal of the field coils wound about the poles, without disturbing the mount of the armature.

, Another object of the invention is the provision ,of an improved circuit controller in which an electromagnetical driving element of rigid construction is directly connected to a rigid operated member carrying a liquid contact tube, by means of a spring adapted to efFect a snap operation of the contact tube to quickly make and break an electrical circuit of which the electrical means which operates the driving element forms a part.

Other objects and advantages of the invention will be apparent from the following description and from the accompanying drawing in which Fig. 1 is a front elevation of a circuit controller embodying the present invention; ,1 Fig. 2 is a vertical section through the controller box or. casing showing the controller mechanism in side elevation;

Fig. 3 is a rear elevational view of the controlling mechanism removed from the box; and,

Fig. a is a schematic diagram of the electriical connections.

In the illustrated embodiment of the invention, forming a preferred form thereof,

No. 816,840. Renewed February 7, 1930.

s16 operating mechanism of the circuit controller is enclosed in a box or easing composed of the rear section and the front section 11, the section 10 having provisions by which it may be easily attached or hung in any desired location. The front section of the box is adapted to be fixed in place by cap nuts 12 mounted on the threaded ends of the rods 13 which extend from the rear section 10. Preferably the two sections engage as indicated at 1% making use of a compressible strip 15 between the engaging portions of the box for the exclusion of nois nre. As shown the joint between the casing sections is about midway between the front and rear casing surfaces to pe mit ready access to the mechanism within the case.

The circuit controller is adapted to automatically control the making and breaking of an external electric circuit connected to a load of any sort such as an electric lamp or lamps. The mechanism comprises a supporting member 18, preferably integral in its construction, to which the various operating parts of the device are connected and supporter. This supporting member embodies a face plate portion 19 adapted to be mounted. in place on the posts 20 of the casing as by means of the screws 21, cork or other suitable yielding and vibration clamping washers 26 being interposed between the supporting member and the casing posts. A bottom plate 22 extends integrally from the lower end of the face plate 19 and supports a back plate 23 parallel with the face plate 19. The bottom plate extends between the two pole pieces 24 of an electromagnet, these pole pieces being formed of U-shaped laminations clamped tightly by screws 25 to the rear side of the face plate 19. The screws 25 are threaded into the face plate, and their headed portions are in engagement with the rear side 01' the laminated electromagnet.

Each of the poles of the electromagnet is provided with a field coil 27, the two coils preferably being connected in series. These coils are easily removed from the laminated pole pieces by slipping them upwardly towards the open end of the magnet after the pole pieces have been disconnected from the face plate 19 by the removal of the screws 25. It 1s therefore apparent that the replacement of burnt out or in ured field coils is very easily accomplished.

The back )late 23 which takes no cart 1n 7 l the su inert of the )ole nieces of the electromagnet supports a antifriction bear-111g preferably of the ball type as indicated at 29. A similar ball bearing 30 is supported in the face plate 1.9 of the supporting mem ber, these ball bearings serving to rotatably support ashaft 31, which is fixed to the iron armature 32 by means of set-screws 33, which are threaded into the armature so as to engage at their inner ends with the shaft 31 to permit the adjustable setting of the armature on the shaft. This armature is preferably laminated and of the so-called Z-type. The body portion of the armature is extended as indicated at 34 at its outer portions so that a magnetic path with small air gap is always maintained between the opposite pole pieces, the armature being caused to move comparatively slowly and without impact when the field coils are energized, this movement occurring in a clockwise direction as viewed in Fig. 3.

Fixed to the armature shaft 31 is an angle piece 36, a small setscrew 37 serving to adjustably fasten the angle piece to the shaft. This piece 36 embodies a laterally extending arm 38 to which isrigidly connected a weight 39 as'by means of the set-screw 0. The weight 39 as shown is slotted or bifurcated at its upper )ortion to receive the arm 38, and the set-screw i0 is threaded into the forward side of the bifurcated portion so as to engage in a groove 41 in the arm 33. The weight 39 n ay thus be adjustably positioned in any desired location along the arm 38 to cause the armature to b moved clockwise (as viewed in Fig. 1) after the electromagnet has been deenergized the turning force being variable in accordance with the positioning of the weight.

he angle piece 36 also embodies an upwardly extending arm 4-2, the upper end of which is preferably turned over forwardly as indicated at 43 for the support of a screw 44; threaded in the overturned portion 43 and adjustably held in position by means of a lock nut 45. The screw 44- is connected at its lower end with a spring 46, the opposite end of which is connected to the bottom of an arm 48 which forms a part of a rigid operated member pivotally mounted prefer ably above and parallel to the shaft 31 by means of a screw 49, which is threaded into an u standing bag 50 provided on a forwardly extending ledge portion 51 of t 1e supporting member 18. It will be apparent that the angle arm 36, the weight 39, the shaft 31 and the armature itself all being rigidly connected together, form a composite rigid driving element which is operated in one di rection by the electromagnetic force of the field magnet, and operated in the other direction by the adjustable weight 39, these motions being effective on the pivoted arm 48 through the action of the spring 46 which noves first to one side and then to the other side of the axis of the shaft 31 to cause a snap actionfirst to one side and then to the other of arm 48. The biasing effect of the spring 46 is adjusted by turning the screw as for proper operation.

The arm i8 is preferably an integral part of a post 53, shown in the form of a metal stamping, these parts providing a rigid operated member for the support of contact making and breaking means. Any suitable number of such contact making and breaking means may be held by the operated member but for purposes of illustration a single means of this character has been shown. The post 53 at its upper end supports a holding spring clip 54 in which is removably mounted a tube 55, preferably of glass, and containing a suitable quantity of electrically conductive fluid such as mercury as indicated at 56. The glass also contains a pair of contacts at one end thereof which are adapted to be bridged by ,the mercury when the mercury is at that end of the tube. These contacts are electrically connected to flexibt wires 57 and 53 which extend to a small contact or connection panel 59 preferably formed of bakelite or other suitable insulating material. Supported on the operated member and closely adjacent the screw as about which the latter pivots, is an insulating block 60 formed of a rear section 61 and a cap section 62, the rear section 61 having grooves through which the wires 57 and 58 may extend, the wires being held in these grooves by means of the cap section 62, which is retained in place by the screws The weight of the wires 57 and 58 where the latter hang from the contact tube is therefore supported to a large extent by this wire-supporting block, and the comiaratively small portion of the wires whose weight is effective on the end of the contact tube is maintained constant so as not to interfere with the snap operation and the timing of the apparatus.

The forward corners of the ledge portion 51 of the supporting member holds two stop screws 65, these screws being threaded in the ledge portion 51 to extend a suitable short distance below the bo'tom surface of this ledge portion. Short springs 66 pressing at one end against the top of the ledge portion and at the other end against the screw head prevent any undesired turning of the screws but permits their easy manual adjustment. These screws serve to limit the motion of the pivoted operated member, the latter being provided with rearwardly extending arms 67 spaced a suitable small distance below the ends of the screws to permit a suitable angular motion of the operated member. Preferably the operated member is stopped in its angular motion in a comparatively gradual and shock-absorbing manner by means of a yielding leaf spring 68 fastened at 69 to a third and central-rearwardly extending arm 70 of the operated member, this spring 68 being upwardly bowed so as to normally have its end portions some little distance away from the rearwardly extending arms 67. However when the operated member moves to one limit of its motion as shown at the left in Fig. 3, the

end of the spring 68 is forced down against the arm 67 by its engagement with the adjacent screw 65, thus absorbing the stopping shock in'a comparatively gradual manner.

' The angular motion of the operated member may be easily adjusted by adjustment of the positions of the screws 65 which may be made to contact sooner or later with the ends of the spring 68, and with the arm 67. The arrangement is also such that, in case the controller 6 is supported slightly out of vertical, one of the screws 65 may be screwed further into the ledge portion 51 while the other is being unscrewed slightly so that the pivotedv operated'member moves equal angular amounts on each side of the vertical.

The ledge portion 51 of the supporting member extends out integrally as indicated at 72 above the laterally projecting weight arm 38. This portion 72 of the ledge member is provided with a threaded part 73 so that a damping casing or cylinder 74 may be supported thereon, this cylinder being formed of a suitable self lubricating composition not affected by temperature changes. The upper portion of this cylinder is pro vided with an orifice 75 closed to any suitable degree by a needle 76 which is carried on a threaded shaft 77 threaded in the cylinder and attached to a knurled screw 78 adapted to be turned by the fingers. A coil spring 79 engaging against the thumb screw 7 8- and against the top of the cylinder prevents undesired rotation of the thumb screw and yieldingly holds it in position. lVithin the cylinder is a piston 80 having a central downwardly extending tongue 81 integral therewith or rigidly fixed thereto, this tongue being pivotally connected at 82 with a link 83 pivotally connected to the arm 38. The rigiddriving element is thus mechanically connected to the damping mechanism by a simple link connection, embodying a minimum of articulate connections so that the speed at which the driving element moves in either direction is governed by the damping mechanism. The time interval during which the weight is effective in causing a clockwise movement of the armature and oftherigid driving element may be adjusted so that it is greater, equal to, or less than the time interval during which the field magnet coils are effective in causing a counter-clockwise movement of the driving element, by suitably positioning the weight 89 on the weight arm of the driving element, and by properly positioning the armature on the armature shaft.

To provide for considerable change in the ratio of the time of energization of the load to the time of deenergization, the piston is shown provided with a check valve 85. This check valve may comprise a ball 86 retained by a slot-ted cap 87 set in the piston, the ball olosingoan air passage 88 in the piston when the latter moves upwardly but permitting some flow of air through the valve when the piston moves down so that the downward movements of the piston take place much faster than the upward movements.

The contact panel 59 is preferably located adjacent the front of the bottom portion of the field magnet. Preferably this panel is mounted on a strap 90 the ends of which are attached to posts 91 extending from the rear casing portion, by means of screws 92. These screws 92 also extend through holes in a bar 93, and the bar 93 is directly fastened by screws 94 threaded at their ends in intermediate portions of the bar 93 and extending through the lower part of the magnet laminations below the field coils. Preferably a cork strip 95 is interposed between the front magnet lamination and the bar 93 so as to mount the magnet on the casing through a shock-absorbing strip of material. The effect of this shock-absorbing strip of cork is to shield vibration of the magnet from the casing.

The contact panel 59 supports contact plates 97, 98, 99 and 100, four of these contact plates being used in apparatus having a single circuit breaking tube as shown, although an additional contact plate or plates may be employed where the apparatus has two contact breaking tubes. The contact plates 98 and 99 are directly connected respectively to the wires 57 and 58 which extend to the tube contacts, and are adapted to be connected respectively to a line wire 101 and to a load wire 102, the load being indicated at 108 in Fig. 4. The contact stri 97 is shown connected to a resistance element 104 supported in any suitable manner, this resistance element being in series with the field coils, as shown. The contact plate is electrically connected to the plate 99 and also connected by a wire 106 to the plate 97. The contact plate 100 is adapted to be connected to the other side of the load 103 and the contact plate 97 is adapted to be connected to the other side of the line as indicated at 107. The various line and load Wires enter the casing through holes 108,

preferably three in number, provided in the rear portion of the casing directly below the operating mechanism of the apparatus. It will be apparent that by reason of these connections the electric circuit through the field coils of the magnet may be i itcrrupted, and the load circuit is interrupted when the con tact tube is moved to interrupt electrical communication between the contacts in the tube. And when this occurs the weight 39 immediately becomes effective so as to return the driving element into position to again make circuit through the contacts and through the field coils. here the resistance 104 is used the use of the apparatus with direct current, and also with very low fre quency alternating current such as twentyfive-cycle current is permitted. The resistance 104 may be omitted or cut out of circuit or bridged across to adapt the apparatus for use with sixty-cycle current. A. single instrument is thus adapted to operate under varying conditions of frequency and voltage, since it is apparent that the resistance may be changed as desired so as to compensate for differences in voltage at various localities.

Where the apparatus is to be used in such a locality as to cause possible undesirable effects on radio apparatus in its proximity a condenser 110 may be employed, connected across the contact plates 98 and 99 or in other words across the break in the circuit through the contact tube. This condenser, which may be screwed to or supported in any suitable manner from the casing, acts an electrical damping means for electrical oscillations of high frequency and prevent such oscillations from being propagated out into the lines.

The particular connection between the driving element and the operated member, embodying the spring connection as described, is one which inherently operates with a minimum of friction, and is furthermore particularly advantageous in an apparatus of this character since the operated member on which the mercury tube is held is yieldinglyheld in both of its limiting positions so that rattle of the parts which might otherwise be caused by the vibrations of the electromagnet 1 coils is obviated. Furthermore the driving element and the operated member, being of rigid construct-ion throughout, and being directly connected by the spring 46, provides a construction in which noise and rattle producing oints and articulations are absent. The ball bearing support of the armature shaft is also conductive to noiseless operation.

The manner in which the various parts of the apparatus are connected to a main supporting member provides a construction in which the parts may be very easily sembled, and in which any of the parts may be taken down without disturbing other operating parts of the apparatus. For example, the damping mechanism may be readily disconnected, for repair or replacement, from the supporting member and from the driving element. And the pivoted operating member which carries the contact tube may be very easily disassociated or dis connected from the driving element by merely disconnecting one end of the spring 46 and removing the pivot screw 19. The entire operating mechanism may be readily disconnected from the casing in which it is supported by merely removing the screws 21 and the screws 92, and after thus being separated from the casing, the field coils of the magnet may be readily disconnected by unscrewing the screws 25 to permit replacement or repair of the coils. This does not disturb the mounting of the armature and of the driving element of which the armature forms a part. The driving element also may be readily disconnected from the supporting member by removing the screws which fasten the" armature and the angle piece 36 to the armature shaft, and then removing the ball bearings which support the armature shaft. This can be done without disturbing the connection of the field mag net with the supporting member. The arrangement, therefore, is one which permits of ease of assembly, repair and inspection, these operations being readily effected to some extent without removing the main part of the apparatus from the casing since the latter is divided in a plane considerably displaced in a rearward direction from the front of the operating mechanism.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

lVhat is claimed is:

1. A circuit controller of the class described comprising a field magnet provided with pole pieces, a field coil cooperating with said pole pieces a movable armature mounted between said pole pieces and movable therebetween without impact ongagement therewith, a rigid operated member pivotally mounted adjacent said armature, operating connections between said operated member and said armature to give a snap movement in opposite directions to the operated member from opposite movements of said armature, a tube carried by said operated member, contacts and fluid means within said tube adapted when the operated member is oscillated to one position to close a circuit and connect the field coil to a current source and when the tube is oscillated to another position to open the circuit, and a single integral supporting member providing opposed bearing mounts for said armature and to which the pole pieces of the field magnet are rigidly connected.

2. A circuit controller of the class described comprising a field magnet provided with pole pieces, a field coil cooperating with said pole pieces, a movable armature mounted between said pole pieces and movable therebetween without impact engagement therewith, a rigid operated member pivotally mounted adjacent said armature, operating connections between said operated member and said armature to give a snap movement in opposite directions to the operated member from opposite movements of said armature, a tube carried by said operated member, contacts and fluid means within said tube adapted when the operated member is oscillated to one position to close a circuit and connect the field coil to a current source and when the tube is oscillated to another position to open the circuit, and a single integral supporting member providing opposed bearing supports for said armature to which the pole pieces of the field magnet are rigidly connected, said supporting member providing a support to which the operated member is pivoted in parallelism with the axis of the said armature.

3. A circuit controller of the class described comprising a field magnet provided with polepieces, a field coil cooperating with said pole pieces, a movable armature pivotally mounted between said pole pieces, a rigid operated member pivotally mounted adjacent said armature, operating connections between said operated member and said armature to give a snap movement in opposite directions to the operated member from opposite movements of said armature, a tube carried by said operated member, fiuid means within said tube and a pair of contacts at one end of said tube adapted when the operated member is oscillated to one position to close the circuit and when oscillated to another position to open the circuit, wires extending from said contacts externally of the tube, and means closely adjacent the pivotal axis of the operated member for guiding said wires.

4. A circuit controller of the class described comprising a field magnet provided with pole pieces, a movable armature mounted between said pole pieces, a rigid supporting member to which said pole pieces are fixed and providing a bearing for the armature, a rigid driving element fixed to the armature, a rigid operated member pivotally connected to said support, a spring directly interconnecting the driving element and the operated 'member to give a snap movement ofthe operated member in opposite directions as the armature moves in opposite direction about its axis, a weight adjustably connected to said rigid driving element and acting to rotate the armature one direction, and a circuit closing and breaking tube fixed to said operated member.

5. A circuit controller of the class described comprising a field magnet provided with pole pieces, a movable armature mounted between said pole pieces, a rigid supporting member to which said pole pieces are fixed and providing bearings at opposite ends of the armature, a rigid driving clement fixed to the armature, a rigid operated member pivotally connected to said support, a spring directly interconnecting the driving element and the operated member to give snap movement of the operated memher in opposite directions as the armature moves in opposite directions about its axis, a weight adjustably fixed directly on said ri id driving element and acting to rotate the armature in one direction, and a circuit closing and breaking tube fixed to said operated member for controlling the energization of the field magnet.

6. A circuit controller of the class described comprising a field magnet provided with pole pieces, a field coil cooperating with said pole pieces, a movable armature mounted between said pole pieces and movable therebetween without impact engagement therewith, a ri id operated member pivotally mounted adjacent said armature, operating connections between said operated member and said armature to give a snap movement in opposite directions to the operated member from opposite movements of said armature, adjustable stops in alternate yielding engagement with said operated member for limiting the movements thereof as desired, a tube carried by said operated member, contacts and fluid means within said tube adapted when the operated member is oscillated to one position to close a circuit and connect the field coil to a current source and when the tube is oscillated to another position to open the circuit, and a single integral supporting member providing opposed bearing mounts for said armature and to which the pole pieces of the field magnet are rigidly connected.

7. A circuit controller of the class described comprising a field magnet provided with pole pieces, a movable armature mounted between said pole pieces, a rigid supporting member to which said pole pieces are fixed and providing a bearing for the armature, a rigid driving element fixed to the armature, a rigid operated member pivotally connected to said support, a spring intcrconnecting the driving element and the operated member to give a snap movement of the operated member in opposite directions as the armature moves in opposite directions about its axis, individually adjustable stops determining the limits of movement 03": the operated member against which the operated member is biased by said spring, I ieans independent of said field magnet for turning said armature in one direction, and circuitmaking and breaking means carried by said operated member for controlling the energization of said magnet.

8. A circuit controller oi the class described comprising a field magnet provided with. pole pieces, a movable armature mounted between said pole pieces, a rigid supporting member to which said pole pieces are fixed and providing bearings at opposite ends of the armature, a rigid driving element fixed to the armature, a rigid operated member pivotallyconnected to said support, a spring directly interconnecting the driving element and the operated member to 'ive a snap movement of the operated member in opposite directions as the armature moves in opposite directions about its axis, adjustable stops on said supporting member deter mining the limits of movement of the operated member against which the operated member is biased by said spring, yielding means for cushioning the engagement of the operated member with said stops, a weight adjustably fixed directly on said rigid driving element andacting to rotate the arma ture in one direction, and a circuit closin and breaking tube 'xed to said operatet member for controlling the energization of the field magnet.

9. A circuit controller of the class described comprising electromagnetic means, an armature operated thereby, a rigid operated member pivotally mounted adjacent said armature, operating connections between said operated member and said armature to give a snap novement in opposite directions to the operated member from opposite movements of said armature and embodying a spring for yieldingly maintaining said operated member in one or theother of its limiting positions, a tube carried by said operated member, fluid means within said tube and a pair of contacts at one end of said tube adapted whenthe operated member is oscillated to one position to close the circuit and when oscillated to another position to open the circuit, wires extending from said contacts externally of the tube, and means closely adjacent the pivotal axis of the operated member for guiding said wires.

10. A circuit controller of'the class described comprisinga field magnet provided with pole pieces, a field coil cooperating with sai d pole pieces, a movable armature mom ited between said pole pieces and movable therebetween without impact engagement therewith, a rigid operated member pivotally mounted adjacent said armature, operating connections between said operated memher and said armature to give a snap move ment in opposite directions to the operated member from opposite movements of said armature, a tube carried by said operated member, contacts and fluid means within said tube adapted when the operated member is oscillated to one position to close a circuit and connect the field coil to a current source and when the tube is oscillated to another position to open the circuit, a single integral supporting member providing opposed bearing supports for said armature to which the pole pieces of the field magnet are rigidly connected, said supporting memer providin a support to which the operated member is pivoted in parallelism with the axis or" the said armature, a casing, means attaching said supporting member to the casing, a contact panel having electrical connection to said tube contacts, and means for attaching said contact panel and said field magnet to the casing.

11. A circuit controller of the class described comprising an electromagnct having adajcent pole pieces, and a rotatably movable armature between said pole pieces, circnit controlling means operated by said armature, said circuit controlling means being adapted when oscillated to one position to close a circuit and connect the electromagnet to a current source and when oscillated to another position to open the circuit, and an integral supporting member providing spaced bearing mounts for said armature and to which the electromagnct is directly rigidly secured.

12. A circuit controller of the class described comprising an electromagnct having a plurality of pole pieces, a movable armature associated with said pole pieces, circuit controlling means pivotally mounted adjacent said armature and including electrical contacts adapted when the'ci'rcuit controlling means is oscillated to one position to close a circuit and energize the electromagnet and when oscillated to another position to open the circuit and deenergizc the electromagnct, operating means between said circuit controlling means and said armature, an integral supporting member providing opposed bearing mounts for said armature and on which the pole pieces of the magnet are directly supported, and a casing in which the supporting member is removably mounted.

13. A circuit controller of the class described comprising an electromagnct, a 1'0- tatably movable armature associated with said electromagnct, a mercury tube operated by said arn ature and adapted to energize the electromagnct and close a circuit when oscillated to one position and when oscillated to another position to open a circuit and deenergize the electromagnet, a small coinpact rigid supporting member providing bearing mounts for said armature, the elec tromagnet being connecteo rigidly to and supported by said supporting member so as to extend downwardly therefrom, and means for directly supporting said supporting member.

14:. A circuit controller of the class described comprising an electromagnet, a rotatably movable armature associated therewith, a mercury tube pivotally mounted adjacent said armature, an operating connection between said mercury tube and said armature, dashpot means for controlling the duration of closed circuit condition of said tube, means for controlling the duration of open circuit condition of said tube and including a weight, and a single unitary driving member attached to said armature and provided in said operating connection, the weight being adjustably mounted directly on said driving member.

15. A circuit controller of the class described comprising an electromagnet and a pair of pole pieces, a movable armature associated therewith, circuit controlling means pivotally mounted adjacent said armature, an operating connection between said circuit controlling means and said armature, said circuit controlling means being adapted when oscillated to one position to close a circuit and energize the electromagnet and when oscillated to another position to open the circuit, means for controlling the dura tion of open circuit condition or" said circuit controlling means, means for independently controlling the duration or" closed circuit condition of said circuit controlling means, a single unitary driving member attached to said armature and provided in said operating connection, and a single integral supporting member providing opposed bearing mounts for said armature and to which the said pole pieces of the electromagnet are rigidly connected.

16. A. circuit controller of the class described comprising a field magnet provided with pole pieces, a field coil cooperating with said pole pieces, a movable armature mounted between said pole pieces and movable therebetween without impact engagement therewith, a rigid operated member pivot-ally mounted adjacent said armature, a tube carried by said operated member, contacts and fluid means within said tube adapted when th operated member is os cillated to one position to close a circuit and connect the field coil to a current source and when the tube is oscillated to another position to open the circuit, and a single integral supporting member providing opposed sign atu re.

GISBERT L. BOSSARD. 

